Reproductive System

1
Reproductive System

• Function produce sex cells (gametes) for
  fertilization

2
How are sex cells produced?

• Sex cells (gametes) are produced by the process
  called meiosis
• Each sex cell has 23 chromosomes
• 4 cells are produced in each cycle of meiosis

3
Why do sex cells undergo meiosis instead of
mitosis?

• In mitosis, 2 cells are produced (each containing
  46 chromosomes).
• All normal cells of the body want 46 chromosomes
• In fertilization, a sperm and egg unite to form a
  zygote.
• If each cell (sperm and egg) had 46 chromosomes
  then the fertilized egg (zygote) would have 92
  chromosomes (not what we want)
• (46) (46) 92
• We want to have 46 in the
• fertilized egg, so the sperm
• and egg need to have
• 23 chromosomes (meiosis)
• (23) (23) 46

4
Sperm production

• Male sex cells are called sperm
• there are 4 sperm produced in each cycle of
  meiosis
• The process of making sperm is called
  spermatogenesis
• Sperm cells are released for fertilization by
  ejaculation

5
Egg production

• Female sex cells are called eggs
• In the process of meiosis, 4 cells are produced
• Making of egg cells is called oogenesis
• only 1 is an egg (also called oocyte)
• -the other 3 are polar bodies that nourish
• egg
• polar bodies

6
Why are more sperm produced than eggs?

• Female male
• 1 egg cell 4 sperm cells
• 3 polar bodies
• In each meiosis cycle, there are 4 sperm produced
  and only 1 egg.
• Why?
• There must be more sperm (millions) in order to
  increase the chances of fertilization. Very few
  sperm make complete the journey to the egg in the
  uterus.

7
Fertilization
8
How does the spermpenetrate the egg?

• The egg has a layer around it that tries to keep
  things from penetrating it.
• The sperm has a structure called an acrosome that
  releases enzymes that break through the layer
  allowing penetration.
• The sperm cell also has a mitochondria which
  provides it energy to get to swim up the uterus
  to the egg.

9
Male reproductive structures

• Scrotum- houses the testes
• Testes- produces the sperm
• Sperm must be 2 degrees less than the body
  temperature or they will die
• The scrotum holds the testes away from the body
  to keep the sperm cooler.
• Temperature affects the skin around the scrotum
• It shrinks which draws the testes close to the
  body when cold.
• It relaxes which moves the testes away when it is
  hot or in exercise.

10
Male anatomy continued

• Ducts
• Epididymus (connects to the testes)
• Sperm mature here
• Once sperm matures in the epidymus, the sperm
  travels thru the vas deferens to the seminal
  vesicle.
• The seminal vesicle holds/stores the sperm until
  ejaculation occurs. It joins the ejaculatory duct
  and the urethra.
• When sperm are ready to be released during
  intercourse, they exit thru the ejaculatory duct
  out the urethra.
• Urethra- extends from the urinary bladder to the
  end of the penis. It releases 1. urine and 2.
  semen

11
Male anatomy continued

• Penis
• Function transfer sperm to the female
• Has 3 layers of erectile tissue
• Increase of blood causes erection
• The skin has many sensory receptors
• Loose fold of skin (foreskin) on the penis is
  removed when someone is circumcised.

12
Male secretions (semen)

• Mixture of sperm cells and gland secretions.
• The fluid is used to help propel sperm and
  contains sugar to nourish sperm
• Volume is 2-5 ml and around 20 million sperm per
  ml

13
Male puberty

• Events in which a child changes to an adult
• The hormone testosterone causes enlargement of
  genitals and the reproductive system
• It encourages development of secondary sexual
  characteristics like behavior changes, voice, and
  beard.
• Testosterone also increases the sex drive

14
Female reproductive system

• Functions
• 1. Produce and maintain the eggs (ovaries)
• 2. Transport eggs to the site of fertilization
• 3. Provide environment for offspring to develop
• 4. Move offspring to outside (labor)
• 5. Produce female sex hormones (ovaries)

15
Female reproductive system

• Ovaries (2)- structures that produce the eggs
• They are attached to the uterus
• The cells the ovaries form are called oocytes
  (immature egg).
• The mature eggs are released in ovulation which
  is influenced by the hormone estrogen (typically
  1/month)

16
Egg production

• Egg production begins early in a childs
  development. How?
• Meiosis begins but the process halts/stops in
  development and does not continue until the girl
  reaches puberty.
• The immature eggs are in clumps called follicles.
• Each month, an oocyte is stimulated to mature
  (cont.. Meiosis) and is releasedready to be
  fertilized.
• On average, the ovary releases 400-500 oocytes
  during a females reproductive life.

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Female anatomy continued..

• Fallopian tubes (uterine tubes or oviducts)- has
  cilia that sweep the egg toward uterus
• About 10 cm (4 in) long
• Has finger-like extensions that move the egg
  called fimbriae
• Also has cilia that line tube to push egg
• Sperm swims here to fertilize egg
• Uterus- fertilized egg (zygote) develops here

18
Uterus cont

• Before the embryo can develop it must implant on
  the uterine wall
• Expands 500 times normal size during pregnancy
• Uterine wall has 3 layers
• 1. Endometriuminnermost layer
• 2. Myometriumthick middle, muscular layer
• 3. Perimetrium outmost layer

19
Female anatomy cont

• Cervix- passage from the uterus to the vagina
• Dilates/expands at time of birth
• Vagina- behind urinary bladder and in front of
  rectum
• 3 functions
• Receive penis
• Menstrual flow
• childbirth

20
External female anatomy

• External female genitalia- vulva
• Clitoris erectile structure that has many
  sensory receptors used for stimulation
• Vestibular gland releases lubricating fluids

21
Problem cysts

• Sometimes cysts will form which disrupts release
  of egg (ovulation)
• Cystfluid filled sac
• Why form? The follicles that hold the oocyte
  enlarge but the egg is not properly released
• Produce too many hormones which inhibit proper
  ovulation patterns. Oocyte stays within ovary
• Many people with cysts in ovaries have difficulty
  having children
• Swollen follicles cause pain

22
Mammary glands

• Function Organs to produce milk found in breasts
• Males and females have these but they only
  develop fully in females at puberty
• When develop, glands/ducts form and fat develops
  between them.
• Glands do not produce and secrete milk until
  hormonal changes occur during pregnancy
• Nipples- sensitive to touch and channel milk
• Gynecomastia- when a male has enlarged breasts

23
Breast cancer

• 1 in 8 women develop breast cancer
• About 1 of breast cancer cases occur in men
• Tends to be genetic
• mammograms are best tools to diagnose
• Treatment lumpectomyremove tumor and small
  amount of tissue
• Mastectomyremove entire breast
• Both involve radiation and/chemo

24
Female puberty

• May appear as early as 8
• Completed usually by age 16
• Marked by the 1st menstrual cycle
• Controlled by the hormones estrogen and
  progesterone

25
Menstrual cycle

• Each cycle lasts around 28 days
• The purpose of the cycle is to provide an egg
  monthly for fertilization.
• Occurs in non pregnant women.
• Menses-the period of bleeding in which the lining
  of the uterus is expelled if one is not pregnant
• The beginning of the cycle is the 1st day of
  bleeding

26
Menstrual cycle

• Day 1- bleeding begins (menses)
• Lasts normally 4-5 days
• Day 14- ovulation (release of egg to uterus)
• The egg will stay in the uterus 7-8 days.
• If fertilization occurs, then the zygote will
  begin to grow in the uterus (cycle will stop).
• If the egg is not fertilized, then it is removed
  from the body in menses (around day 28).
• The onset of menses is triggered by the
  progesterone level decreasing when not pregnant.

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PMS (premenstrual syndrome)

• Hormone levels (estrogen and progesterone) change
  just before menses
• The hormone levels affect mood, water retention,
  headaches, cramps
• Menstrual cramps- due to contraction of the
  uterus lining to release the inner layer of the
  uterus (inflammation)

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Menopause

• Stopping off the menstrual cycle
• Ovulation decreases with age due to decrease in
  the number of eggs
• Symptoms of onset due to decreased hormone
  levels
• Hot flashes, irritability, fatigue, anxiety,
  emotional disturbances
• Treated by taking estrogen (increase hormone
  levels)

29
Contraceptives

• Only 100 birth control is abstinence
• May purchase these or have surgeries
• 2 surgeries
• 1. Vasectomy- cutting of the vas deferens to
  prevent sperm from leaving the testes
• 2. Tibal ligation- uterine tubes are tied and
  cut

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Sexually transmitted diseases

• Known as STDs
• There are 20 of these that are recognized
• Called silent infections because do not produce
  symptoms in early stages
• By the time symptoms appear, too late to prevent
  complications and spread to partner
• May result in inability to have children

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Common symptoms of STDs

• 1. burning when urinate
• 2. lower abdominal pain
• 3. fever or swollen glands in neck
• 4. discharge from vagina or penis
• 5. pain, itching, inflammation in genital area
• 6. pain during intercourse
• 7. sores, blisters, bumps, rashes on body, mouth,
  or genitals

32
6 most common STDs

• Acquired immune deficiency syndrome
• Chlamydia infection
• Genital herpes
• Genital warts
• Gonorrhea
• Syphilis

33
Acquired immune deficiency syndrome (AIDS)

• Cause human immunodeficiency virus (HIV)
• Symptoms fever, weakness, infections, cancer
• Treatment no cure, drugs to help symptoms

34
Chlamydia infection

• Cause bacteria called chlamydia
• Symptoms painful urination and intercourse,
  mucous discharge from vagina or penis, sores
• Treatment antibiotics

35
Genital herpes

• Cause herpes simplex 2 virus
• Symptoms genital sores, fever
• Treatment antiviral drugs
• Can not ever rid body of it

36
Genital warts

• Cause human papilloma virus (very commonly
  spread)
• Symptoms often has periods of dormancy and then
  periods of activity
• Warts on genitals or anywhere else on body,
  abdominal pain
• Treatment no cure, remove warts surgically or
  chemically
• There is a vaccination for this but must be taken
  before exposed to it, not after

37
Gonorrhea

• Cause neisseria gonorrhoeae bacteria
• Symptoms in women no symptoms often, some
  discharge
• in men, painful urination, rash, swollen
  genitals, discharge occur in eyes, throat,
  genitals
• Common affected sites are eyes, throats, genitals
• Treatment antibiotics

38
Syphilis

• Cause treponema pallidum bacteria (passed thru
  contact from sores)
• Occurs in stages
• Symptom
• primary stage chancre sore on genitals or mouth,
  
• secondary stage rash 6 months later,
• latent stage may have several years with no
  symptoms as it spreads, damage to heart, liver,
  nerves, brain occur
• Treatment antibiotics